drivers/md/bitmap.c

   1 /*
   2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   3  *
   4  * bitmap_create  - sets up the bitmap structure
   5  * bitmap_destroy - destroys the bitmap structure
   6  *
   7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
   8  * - added disk storage for bitmap
   9  * - changes to allow various bitmap chunk sizes
  10  */
  11
  12 /*
  13  * Still to do:
  14  *
  15  * flush after percent set rather than just time based. (maybe both).
  16  */
  17
  18 #include <linux/blkdev.h>
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/slab.h>
  22 #include <linux/init.h>
  23 #include <linux/timer.h>
  24 #include <linux/sched.h>
  25 #include <linux/list.h>
  26 #include <linux/file.h>
  27 #include <linux/mount.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/seq_file.h>
  30 #include "md.h"
  31 #include "bitmap.h"
  32
  33 static inline char *bmname(struct bitmap *bitmap)
  34 {
  35         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
  36 }
  37
  38 /*
  39  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  40  *
  41  * 1) check to see if this page is allocated, if it's not then try to alloc
  42  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
  43  *    page pointer directly as a counter
  44  *
  45  * if we find our page, we increment the page's refcount so that it stays
  46  * allocated while we're using it
  47  */
  48 static int bitmap_checkpage(struct bitmap_counts *bitmap,
  49                             unsigned long page, int create)
  50 __releases(bitmap->lock)
  51 __acquires(bitmap->lock)
  52 {
  53         unsigned char *mappage;
  54
  55         if (page >= bitmap->pages) {
  56                 /* This can happen if bitmap_start_sync goes beyond
  57                  * End-of-device while looking for a whole page.
  58                  * It is harmless.
  59                  */
  60                 return -EINVAL;
  61         }
  62
  63         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
  64                 return 0;
  65
  66         if (bitmap->bp[page].map) /* page is already allocated, just return */
  67                 return 0;
  68
  69         if (!create)
  70                 return -ENOENT;
  71
  72         /* this page has not been allocated yet */
  73
  74         spin_unlock_irq(&bitmap->lock);
  75         mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
  76         spin_lock_irq(&bitmap->lock);
  77
  78         if (mappage == NULL) {
  79                 pr_debug("md/bitmap: map page allocation failed, hijacking\n");
  80                 /* failed - set the hijacked flag so that we can use the
  81                  * pointer as a counter */
  82                 if (!bitmap->bp[page].map)
  83                         bitmap->bp[page].hijacked = 1;
  84         } else if (bitmap->bp[page].map ||
  85                    bitmap->bp[page].hijacked) {
  86                 /* somebody beat us to getting the page */
  87                 kfree(mappage);
  88                 return 0;
  89         } else {
  90
  91                 /* no page was in place and we have one, so install it */
  92
  93                 bitmap->bp[page].map = mappage;
  94                 bitmap->missing_pages--;
  95         }
  96         return 0;
  97 }
  98
  99 /* if page is completely empty, put it back on the free list, or dealloc it */
 100 /* if page was hijacked, unmark the flag so it might get alloced next time */
 101 /* Note: lock should be held when calling this */
 102 static void bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
 103 {
 104         char *ptr;
 105
 106         if (bitmap->bp[page].count) /* page is still busy */
 107                 return;
 108
 109         /* page is no longer in use, it can be released */
 110
 111         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
 112                 bitmap->bp[page].hijacked = 0;
 113                 bitmap->bp[page].map = NULL;
 114         } else {
 115                 /* normal case, free the page */
 116                 ptr = bitmap->bp[page].map;
 117                 bitmap->bp[page].map = NULL;
 118                 bitmap->missing_pages++;
 119                 kfree(ptr);
 120         }
 121 }
 122
 123 /*
 124  * bitmap file handling - read and write the bitmap file and its superblock
 125  */
 126
 127 /*
 128  * basic page I/O operations
 129  */
 130
 131 /* IO operations when bitmap is stored near all superblocks */
 132 static int read_sb_page(struct mddev *mddev, loff_t offset,
 133                         struct page *page,
 134                         unsigned long index, int size)
 135 {
 136         /* choose a good rdev and read the page from there */
 137
 138         struct md_rdev *rdev;
 139         sector_t target;
 140
 141         rdev_for_each(rdev, mddev) {
 142                 if (! test_bit(In_sync, &rdev->flags)
 143                     || test_bit(Faulty, &rdev->flags))
 144                         continue;
 145
 146                 target = offset + index * (PAGE_SIZE/512);
 147
 148                 if (sync_page_io(rdev, target,
 149                                  roundup(size, bdev_logical_block_size(rdev->bdev)),
 150                                  page, READ, true)) {
 151                         page->index = index;
 152                         return 0;
 153                 }
 154         }
 155         return -EIO;
 156 }
 157
 158 static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
 159 {
 160         /* Iterate the disks of an mddev, using rcu to protect access to the
 161          * linked list, and raising the refcount of devices we return to ensure
 162          * they don't disappear while in use.
 163          * As devices are only added or removed when raid_disk is < 0 and
 164          * nr_pending is 0 and In_sync is clear, the entries we return will
 165          * still be in the same position on the list when we re-enter
 166          * list_for_each_entry_continue_rcu.
 167          */
 168         rcu_read_lock();
 169         if (rdev == NULL)
 170                 /* start at the beginning */
 171                 rdev = list_entry_rcu(&mddev->disks, struct md_rdev, same_set);
 172         else {
 173                 /* release the previous rdev and start from there. */
 174                 rdev_dec_pending(rdev, mddev);
 175         }
 176         list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
 177                 if (rdev->raid_disk >= 0 &&
 178                     !test_bit(Faulty, &rdev->flags)) {
 179                         /* this is a usable devices */
 180                         atomic_inc(&rdev->nr_pending);
 181                         rcu_read_unlock();
 182                         return rdev;
 183                 }
 184         }
 185         rcu_read_unlock();
 186         return NULL;
 187 }
 188
 189 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 190 {
 191         struct md_rdev *rdev = NULL;
 192         struct block_device *bdev;
 193         struct mddev *mddev = bitmap->mddev;
 194         struct bitmap_storage *store = &bitmap->storage;
 195
 196         while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
 197                 int size = PAGE_SIZE;
 198                 loff_t offset = mddev->bitmap_info.offset;
 199
 200                 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
 201
 202                 if (page->index == store->file_pages-1) {
 203                         int last_page_size = store->bytes & (PAGE_SIZE-1);
 204                         if (last_page_size == 0)
 205                                 last_page_size = PAGE_SIZE;
 206                         size = roundup(last_page_size,
 207                                        bdev_logical_block_size(bdev));
 208                 }
 209                 /* Just make sure we aren't corrupting data or
 210                  * metadata
 211                  */
 212                 if (mddev->external) {
 213                         /* Bitmap could be anywhere. */
 214                         if (rdev->sb_start + offset + (page->index
 215                                                        * (PAGE_SIZE/512))
 216                             > rdev->data_offset
 217                             &&
 218                             rdev->sb_start + offset
 219                             < (rdev->data_offset + mddev->dev_sectors
 220                              + (PAGE_SIZE/512)))
 221                                 goto bad_alignment;
 222                 } else if (offset < 0) {
 223                         /* DATA  BITMAP METADATA  */
 224                         if (offset
 225                             + (long)(page->index * (PAGE_SIZE/512))
 226                             + size/512 > 0)
 227                                 /* bitmap runs in to metadata */
 228                                 goto bad_alignment;
 229                         if (rdev->data_offset + mddev->dev_sectors
 230                             > rdev->sb_start + offset)
 231                                 /* data runs in to bitmap */
 232                                 goto bad_alignment;
 233                 } else if (rdev->sb_start < rdev->data_offset) {
 234                         /* METADATA BITMAP DATA */
 235                         if (rdev->sb_start
 236                             + offset
 237                             + page->index*(PAGE_SIZE/512) + size/512
 238                             > rdev->data_offset)
 239                                 /* bitmap runs in to data */
 240                                 goto bad_alignment;
 241                 } else {
 242                         /* DATA METADATA BITMAP - no problems */
 243                 }
 244                 md_super_write(mddev, rdev,
 245                                rdev->sb_start + offset
 246                                + page->index * (PAGE_SIZE/512),
 247                                size,
 248                                page);
 249         }
 250
 251         if (wait)
 252                 md_super_wait(mddev);
 253         return 0;
 254
 255  bad_alignment:
 256         return -EINVAL;
 257 }
 258
 259 static void bitmap_file_kick(struct bitmap *bitmap);
 260 /*
 261  * write out a page to a file
 262  */
 263 static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 264 {
 265         struct buffer_head *bh;
 266
 267         if (bitmap->storage.file == NULL) {
 268                 switch (write_sb_page(bitmap, page, wait)) {
 269                 case -EINVAL:
 270                         set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 271                 }
 272         } else {
 273
 274                 bh = page_buffers(page);
 275
 276                 while (bh && bh->b_blocknr) {
 277                         atomic_inc(&bitmap->pending_writes);
 278                         set_buffer_locked(bh);
 279                         set_buffer_mapped(bh);
 280                         submit_bh(WRITE | REQ_SYNC, bh);
 281                         bh = bh->b_this_page;
 282                 }
 283
 284                 if (wait)
 285                         wait_event(bitmap->write_wait,
 286                                    atomic_read(&bitmap->pending_writes)==0);
 287         }
 288         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 289                 bitmap_file_kick(bitmap);
 290 }
 291
 292 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
 293 {
 294         struct bitmap *bitmap = bh->b_private;
 295
 296         if (!uptodate)
 297                 set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
 298         if (atomic_dec_and_test(&bitmap->pending_writes))
 299                 wake_up(&bitmap->write_wait);
 300 }
 301
 302 /* copied from buffer.c */
 303 static void
 304 __clear_page_buffers(struct page *page)
 305 {
 306         ClearPagePrivate(page);
 307         set_page_private(page, 0);
 308         page_cache_release(page);
 309 }
 310 static void free_buffers(struct page *page)
 311 {
 312         struct buffer_head *bh;
 313
 314         if (!PagePrivate(page))
 315                 return;
 316
 317         bh = page_buffers(page);
 318         while (bh) {
 319                 struct buffer_head *next = bh->b_this_page;
 320                 free_buffer_head(bh);
 321                 bh = next;
 322         }
 323         __clear_page_buffers(page);
 324         put_page(page);
 325 }
 326
 327 /* read a page from a file.
 328  * We both read the page, and attach buffers to the page to record the
 329  * address of each block (using bmap).  These addresses will be used
 330  * to write the block later, completely bypassing the filesystem.
 331  * This usage is similar to how swap files are handled, and allows us
 332  * to write to a file with no concerns of memory allocation failing.
 333  */
 334 static int read_page(struct file *file, unsigned long index,
 335                      struct bitmap *bitmap,
 336                      unsigned long count,
 337                      struct page *page)
 338 {
 339         int ret = 0;
 340         struct inode *inode = file_inode(file);
 341         struct buffer_head *bh;
 342         sector_t block;
 343
 344         pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
 345                  (unsigned long long)index << PAGE_SHIFT);
 346
 347         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
 348         if (!bh) {
 349                 ret = -ENOMEM;
 350                 goto out;
 351         }
 352         attach_page_buffers(page, bh);
 353         block = index << (PAGE_SHIFT - inode->i_blkbits);
 354         while (bh) {
 355                 if (count == 0)
 356                         bh->b_blocknr = 0;
 357                 else {
 358                         bh->b_blocknr = bmap(inode, block);
 359                         if (bh->b_blocknr == 0) {
 360                                 /* Cannot use this file! */
 361                                 ret = -EINVAL;
 362                                 goto out;
 363                         }
 364                         bh->b_bdev = inode->i_sb->s_bdev;
 365                         if (count < (1<<inode->i_blkbits))
 366                                 count = 0;
 367                         else
 368                                 count -= (1<<inode->i_blkbits);
 369
 370                         bh->b_end_io = end_bitmap_write;
 371                         bh->b_private = bitmap;
 372                         atomic_inc(&bitmap->pending_writes);
 373                         set_buffer_locked(bh);
 374                         set_buffer_mapped(bh);
 375                         submit_bh(READ, bh);
 376                 }
 377                 block++;
 378                 bh = bh->b_this_page;
 379         }
 380         page->index = index;
 381
 382         wait_event(bitmap->write_wait,
 383                    atomic_read(&bitmap->pending_writes)==0);
 384         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 385                 ret = -EIO;
 386 out:
 387         if (ret)
 388                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
 389                         (int)PAGE_SIZE,
 390                         (unsigned long long)index << PAGE_SHIFT,
 391                         ret);
 392         return ret;
 393 }
 394
 395 /*
 396  * bitmap file superblock operations
 397  */
 398
 399 /* update the event counter and sync the superblock to disk */
 400 void bitmap_update_sb(struct bitmap *bitmap)
 401 {
 402         bitmap_super_t *sb;
 403
 404         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
 405                 return;
 406         if (bitmap->mddev->bitmap_info.external)
 407                 return;
 408         if (!bitmap->storage.sb_page) /* no superblock */
 409                 return;
 410         sb = kmap_atomic(bitmap->storage.sb_page);
 411         sb->events = cpu_to_le64(bitmap->mddev->events);
 412         if (bitmap->mddev->events < bitmap->events_cleared)
 413                 /* rocking back to read-only */
 414                 bitmap->events_cleared = bitmap->mddev->events;
 415         sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
 416         sb->state = cpu_to_le32(bitmap->flags);
 417         /* Just in case these have been changed via sysfs: */
 418         sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
 419         sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
 420         /* This might have been changed by a reshape */
 421         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 422         sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
 423         sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
 424                                            bitmap_info.space);
 425         kunmap_atomic(sb);
 426         write_page(bitmap, bitmap->storage.sb_page, 1);
 427 }
 428
 429 /* print out the bitmap file superblock */
 430 void bitmap_print_sb(struct bitmap *bitmap)
 431 {
 432         bitmap_super_t *sb;
 433
 434         if (!bitmap || !bitmap->storage.sb_page)
 435                 return;
 436         sb = kmap_atomic(bitmap->storage.sb_page);
 437         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
 438         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
 439         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
 440         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
 441                                         *(__u32 *)(sb->uuid+0),
 442                                         *(__u32 *)(sb->uuid+4),
 443                                         *(__u32 *)(sb->uuid+8),
 444                                         *(__u32 *)(sb->uuid+12));
 445         printk(KERN_DEBUG "        events: %llu\n",
 446                         (unsigned long long) le64_to_cpu(sb->events));
 447         printk(KERN_DEBUG "events cleared: %llu\n",
 448                         (unsigned long long) le64_to_cpu(sb->events_cleared));
 449         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
 450         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
 451         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
 452         printk(KERN_DEBUG "     sync size: %llu KB\n",
 453                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
 454         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
 455         kunmap_atomic(sb);
 456 }
 457
 458 /*
 459  * bitmap_new_disk_sb
 460  * @bitmap
 461  *
 462  * This function is somewhat the reverse of bitmap_read_sb.  bitmap_read_sb
 463  * reads and verifies the on-disk bitmap superblock and populates bitmap_info.
 464  * This function verifies 'bitmap_info' and populates the on-disk bitmap
 465  * structure, which is to be written to disk.
 466  *
 467  * Returns: 0 on success, -Exxx on error
 468  */
 469 static int bitmap_new_disk_sb(struct bitmap *bitmap)
 470 {
 471         bitmap_super_t *sb;
 472         unsigned long chunksize, daemon_sleep, write_behind;
 473
 474         bitmap->storage.sb_page = alloc_page(GFP_KERNEL);
 475         if (bitmap->storage.sb_page == NULL)
 476                 return -ENOMEM;
 477         bitmap->storage.sb_page->index = 0;
 478
 479         sb = kmap_atomic(bitmap->storage.sb_page);
 480
 481         sb->magic = cpu_to_le32(BITMAP_MAGIC);
 482         sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
 483
 484         chunksize = bitmap->mddev->bitmap_info.chunksize;
 485         BUG_ON(!chunksize);
 486         if (!is_power_of_2(chunksize)) {
 487                 kunmap_atomic(sb);
 488                 printk(KERN_ERR "bitmap chunksize not a power of 2\n");
 489                 return -EINVAL;
 490         }
 491         sb->chunksize = cpu_to_le32(chunksize);
 492
 493         daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
 494         if (!daemon_sleep ||
 495             (daemon_sleep < 1) || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
 496                 printk(KERN_INFO "Choosing daemon_sleep default (5 sec)\n");
 497                 daemon_sleep = 5 * HZ;
 498         }
 499         sb->daemon_sleep = cpu_to_le32(daemon_sleep);
 500         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 501
 502         /*
 503          * FIXME: write_behind for RAID1.  If not specified, what
 504          * is a good choice?  We choose COUNTER_MAX / 2 arbitrarily.
 505          */
 506         write_behind = bitmap->mddev->bitmap_info.max_write_behind;
 507         if (write_behind > COUNTER_MAX)
 508                 write_behind = COUNTER_MAX / 2;
 509         sb->write_behind = cpu_to_le32(write_behind);
 510         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 511
 512         /* keep the array size field of the bitmap superblock up to date */
 513         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 514
 515         memcpy(sb->uuid, bitmap->mddev->uuid, 16);
 516
 517         set_bit(BITMAP_STALE, &bitmap->flags);
 518         sb->state = cpu_to_le32(bitmap->flags);
 519         bitmap->events_cleared = bitmap->mddev->events;
 520         sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
 521
 522         kunmap_atomic(sb);
 523
 524         return 0;
 525 }
 526
 527 /* read the superblock from the bitmap file and initialize some bitmap fields */
 528 static int bitmap_read_sb(struct bitmap *bitmap)
 529 {
 530         char *reason = NULL;
 531         bitmap_super_t *sb;
 532         unsigned long chunksize, daemon_sleep, write_behind;
 533         unsigned long long events;
 534         unsigned long sectors_reserved = 0;
 535         int err = -EINVAL;
 536         struct page *sb_page;
 537
 538         if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
 539                 chunksize = 128 * 1024 * 1024;
 540                 daemon_sleep = 5 * HZ;
 541                 write_behind = 0;
 542                 set_bit(BITMAP_STALE, &bitmap->flags);
 543                 err = 0;
 544                 goto out_no_sb;
 545         }
 546         /* page 0 is the superblock, read it... */
 547         sb_page = alloc_page(GFP_KERNEL);
 548         if (!sb_page)
 549                 return -ENOMEM;
 550         bitmap->storage.sb_page = sb_page;
 551
 552         if (bitmap->storage.file) {
 553                 loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
 554                 int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
 555
 556                 err = read_page(bitmap->storage.file, 0,
 557                                 bitmap, bytes, sb_page);
 558         } else {
 559                 err = read_sb_page(bitmap->mddev,
 560                                    bitmap->mddev->bitmap_info.offset,
 561                                    sb_page,
 562                                    0, sizeof(bitmap_super_t));
 563         }
 564         if (err)
 565                 return err;
 566
 567         sb = kmap_atomic(sb_page);
 568
 569         chunksize = le32_to_cpu(sb->chunksize);
 570         daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
 571         write_behind = le32_to_cpu(sb->write_behind);
 572         sectors_reserved = le32_to_cpu(sb->sectors_reserved);
 573
 574         /* verify that the bitmap-specific fields are valid */
 575         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
 576                 reason = "bad magic";
 577         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
 578                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
 579                 reason = "unrecognized superblock version";
 580         else if (chunksize < 512)
 581                 reason = "bitmap chunksize too small";
 582         else if (!is_power_of_2(chunksize))
 583                 reason = "bitmap chunksize not a power of 2";
 584         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
 585                 reason = "daemon sleep period out of range";
 586         else if (write_behind > COUNTER_MAX)
 587                 reason = "write-behind limit out of range (0 - 16383)";
 588         if (reason) {
 589                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
 590                         bmname(bitmap), reason);
 591                 goto out;
 592         }
 593
 594         /* keep the array size field of the bitmap superblock up to date */
 595         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
 596
 597         if (bitmap->mddev->persistent) {
 598                 /*
 599                  * We have a persistent array superblock, so compare the
 600                  * bitmap's UUID and event counter to the mddev's
 601                  */
 602                 if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
 603                         printk(KERN_INFO
 604                                "%s: bitmap superblock UUID mismatch\n",
 605                                bmname(bitmap));
 606                         goto out;
 607                 }
 608                 events = le64_to_cpu(sb->events);
 609                 if (events < bitmap->mddev->events) {
 610                         printk(KERN_INFO
 611                                "%s: bitmap file is out of date (%llu < %llu) "
 612                                "-- forcing full recovery\n",
 613                                bmname(bitmap), events,
 614                                (unsigned long long) bitmap->mddev->events);
 615                         set_bit(BITMAP_STALE, &bitmap->flags);
 616                 }
 617         }
 618
 619         /* assign fields using values from superblock */
 620         bitmap->flags |= le32_to_cpu(sb->state);
 621         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
 622                 set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
 623         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
 624         err = 0;
 625 out:
 626         kunmap_atomic(sb);
 627 out_no_sb:
 628         if (test_bit(BITMAP_STALE, &bitmap->flags))
 629                 bitmap->events_cleared = bitmap->mddev->events;
 630         bitmap->mddev->bitmap_info.chunksize = chunksize;
 631         bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
 632         bitmap->mddev->bitmap_info.max_write_behind = write_behind;
 633         if (bitmap->mddev->bitmap_info.space == 0 ||
 634             bitmap->mddev->bitmap_info.space > sectors_reserved)
 635                 bitmap->mddev->bitmap_info.space = sectors_reserved;
 636         if (err)
 637                 bitmap_print_sb(bitmap);
 638         return err;
 639 }
 640
 641 /*
 642  * general bitmap file operations
 643  */
 644
 645 /*
 646  * on-disk bitmap:
 647  *
 648  * Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
 649  * file a page at a time. There's a superblock at the start of the file.
 650  */
 651 /* calculate the index of the page that contains this bit */
 652 static inline unsigned long file_page_index(struct bitmap_storage *store,
 653                                             unsigned long chunk)
 654 {
 655         if (store->sb_page)
 656                 chunk += sizeof(bitmap_super_t) << 3;
 657         return chunk >> PAGE_BIT_SHIFT;
 658 }
 659
 660 /* calculate the (bit) offset of this bit within a page */
 661 static inline unsigned long file_page_offset(struct bitmap_storage *store,
 662                                              unsigned long chunk)
 663 {
 664         if (store->sb_page)
 665                 chunk += sizeof(bitmap_super_t) << 3;
 666         return chunk & (PAGE_BITS - 1);
 667 }
 668
 669 /*
 670  * return a pointer to the page in the filemap that contains the given bit
 671  *
 672  * this lookup is complicated by the fact that the bitmap sb might be exactly
 673  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
 674  * 0 or page 1
 675  */
 676 static inline struct page *filemap_get_page(struct bitmap_storage *store,
 677                                             unsigned long chunk)
 678 {
 679         if (file_page_index(store, chunk) >= store->file_pages)
 680                 return NULL;
 681         return store->filemap[file_page_index(store, chunk)
 682                               - file_page_index(store, 0)];
 683 }
 684
 685 static int bitmap_storage_alloc(struct bitmap_storage *store,
 686                                 unsigned long chunks, int with_super)
 687 {
 688         int pnum;
 689         unsigned long num_pages;
 690         unsigned long bytes;
 691
 692         bytes = DIV_ROUND_UP(chunks, 8);
 693         if (with_super)
 694                 bytes += sizeof(bitmap_super_t);
 695
 696         num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
 697
 698         store->filemap = kmalloc(sizeof(struct page *)
 699                                  * num_pages, GFP_KERNEL);
 700         if (!store->filemap)
 701                 return -ENOMEM;
 702
 703         if (with_super && !store->sb_page) {
 704                 store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
 705                 if (store->sb_page == NULL)
 706                         return -ENOMEM;
 707                 store->sb_page->index = 0;
 708         }
 709         pnum = 0;
 710         if (store->sb_page) {
 711                 store->filemap[0] = store->sb_page;
 712                 pnum = 1;
 713         }
 714         for ( ; pnum < num_pages; pnum++) {
 715                 store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
 716                 if (!store->filemap[pnum]) {
 717                         store->file_pages = pnum;
 718                         return -ENOMEM;
 719                 }
 720                 store->filemap[pnum]->index = pnum;
 721         }
 722         store->file_pages = pnum;
 723
 724         /* We need 4 bits per page, rounded up to a multiple
 725          * of sizeof(unsigned long) */
 726         store->filemap_attr = kzalloc(
 727                 roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 728                 GFP_KERNEL);
 729         if (!store->filemap_attr)
 730                 return -ENOMEM;
 731
 732         store->bytes = bytes;
 733
 734         return 0;
 735 }
 736
 737 static void bitmap_file_unmap(struct bitmap_storage *store)
 738 {
 739         struct page **map, *sb_page;
 740         int pages;
 741         struct file *file;
 742
 743         file = store->file;
 744         map = store->filemap;
 745         pages = store->file_pages;
 746         sb_page = store->sb_page;
 747
 748         while (pages--)
 749                 if (map[pages] != sb_page) /* 0 is sb_page, release it below */
 750                         free_buffers(map[pages]);
 751         kfree(map);
 752         kfree(store->filemap_attr);
 753
 754         if (sb_page)
 755                 free_buffers(sb_page);
 756
 757         if (file) {
 758                 struct inode *inode = file_inode(file);
 759                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 760                 fput(file);
 761         }
 762 }
 763
 764 /*
 765  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
 766  * then it is no longer reliable, so we stop using it and we mark the file
 767  * as failed in the superblock
 768  */
 769 static void bitmap_file_kick(struct bitmap *bitmap)
 770 {
 771         char *path, *ptr = NULL;
 772
 773         if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
 774                 bitmap_update_sb(bitmap);
 775
 776                 if (bitmap->storage.file) {
 777                         path = kmalloc(PAGE_SIZE, GFP_KERNEL);
 778                         if (path)
 779                                 ptr = d_path(&bitmap->storage.file->f_path,
 780                                              path, PAGE_SIZE);
 781
 782                         printk(KERN_ALERT
 783                               "%s: kicking failed bitmap file %s from array!\n",
 784                               bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
 785
 786                         kfree(path);
 787                 } else
 788                         printk(KERN_ALERT
 789                                "%s: disabling internal bitmap due to errors\n",
 790                                bmname(bitmap));
 791         }
 792 }
 793
 794 enum bitmap_page_attr {
 795         BITMAP_PAGE_DIRTY = 0,     /* there are set bits that need to be synced */
 796         BITMAP_PAGE_PENDING = 1,   /* there are bits that are being cleaned.
 797                                     * i.e. counter is 1 or 2. */
 798         BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
 799 };
 800
 801 static inline void set_page_attr(struct bitmap *bitmap, int pnum,
 802                                  enum bitmap_page_attr attr)
 803 {
 804         set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 805 }
 806
 807 static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
 808                                    enum bitmap_page_attr attr)
 809 {
 810         clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 811 }
 812
 813 static inline int test_page_attr(struct bitmap *bitmap, int pnum,
 814                                  enum bitmap_page_attr attr)
 815 {
 816         return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
 817 }
 818
 819 static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
 820                                            enum bitmap_page_attr attr)
 821 {
 822         return test_and_clear_bit((pnum<<2) + attr,
 823                                   bitmap->storage.filemap_attr);
 824 }
 825 /*
 826  * bitmap_file_set_bit -- called before performing a write to the md device
 827  * to set (and eventually sync) a particular bit in the bitmap file
 828  *
 829  * we set the bit immediately, then we record the page number so that
 830  * when an unplug occurs, we can flush the dirty pages out to disk
 831  */
 832 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 833 {
 834         unsigned long bit;
 835         struct page *page;
 836         void *kaddr;
 837         unsigned long chunk = block >> bitmap->counts.chunkshift;
 838
 839         page = filemap_get_page(&bitmap->storage, chunk);
 840         if (!page)
 841                 return;
 842         bit = file_page_offset(&bitmap->storage, chunk);
 843
 844         /* set the bit */
 845         kaddr = kmap_atomic(page);
 846         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 847                 set_bit(bit, kaddr);
 848         else
 849                 set_bit_le(bit, kaddr);
 850         kunmap_atomic(kaddr);
 851         pr_debug("set file bit %lu page %lu\n", bit, page->index);
 852         /* record page number so it gets flushed to disk when unplug occurs */
 853         set_page_attr(bitmap, page->index, BITMAP_PAGE_DIRTY);
 854 }
 855
 856 static void bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
 857 {
 858         unsigned long bit;
 859         struct page *page;
 860         void *paddr;
 861         unsigned long chunk = block >> bitmap->counts.chunkshift;
 862
 863         page = filemap_get_page(&bitmap->storage, chunk);
 864         if (!page)
 865                 return;
 866         bit = file_page_offset(&bitmap->storage, chunk);
 867         paddr = kmap_atomic(page);
 868         if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
 869                 clear_bit(bit, paddr);
 870         else
 871                 clear_bit_le(bit, paddr);
 872         kunmap_atomic(paddr);
 873         if (!test_page_attr(bitmap, page->index, BITMAP_PAGE_NEEDWRITE)) {
 874                 set_page_attr(bitmap, page->index, BITMAP_PAGE_PENDING);
 875                 bitmap->allclean = 0;
 876         }
 877 }
 878
 879 /* this gets called when the md device is ready to unplug its underlying
 880  * (slave) device queues -- before we let any writes go down, we need to
 881  * sync the dirty pages of the bitmap file to disk */
 882 void bitmap_unplug(struct bitmap *bitmap)
 883 {
 884         unsigned long i;
 885         int dirty, need_write;
 886         int wait = 0;
 887
 888         if (!bitmap || !bitmap->storage.filemap ||
 889             test_bit(BITMAP_STALE, &bitmap->flags))
 890                 return;
 891
 892         /* look at each page to see if there are any set bits that need to be
 893          * flushed out to disk */
 894         for (i = 0; i < bitmap->storage.file_pages; i++) {
 895                 if (!bitmap->storage.filemap)
 896                         return;
 897                 dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
 898                 need_write = test_and_clear_page_attr(bitmap, i,
 899                                                       BITMAP_PAGE_NEEDWRITE);
 900                 if (dirty || need_write) {
 901                         clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
 902                         write_page(bitmap, bitmap->storage.filemap[i], 0);
 903                 }
 904                 if (dirty)
 905                         wait = 1;
 906         }
 907         if (wait) { /* if any writes were performed, we need to wait on them */
 908                 if (bitmap->storage.file)
 909                         wait_event(bitmap->write_wait,
 910                                    atomic_read(&bitmap->pending_writes)==0);
 911                 else
 912                         md_super_wait(bitmap->mddev);
 913         }
 914         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
 915                 bitmap_file_kick(bitmap);
 916 }
 917 EXPORT_SYMBOL(bitmap_unplug);
 918
 919 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 920 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
 921  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
 922  * memory mapping of the bitmap file
 923  * Special cases:
 924  *   if there's no bitmap file, or if the bitmap file had been
 925  *   previously kicked from the array, we mark all the bits as
 926  *   1's in order to cause a full resync.
 927  *
 928  * We ignore all bits for sectors that end earlier than 'start'.
 929  * This is used when reading an out-of-date bitmap...
 930  */
 931 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
 932 {
 933         unsigned long i, chunks, index, oldindex, bit;
 934         struct page *page = NULL;
 935         unsigned long bit_cnt = 0;
 936         struct file *file;
 937         unsigned long offset;
 938         int outofdate;
 939         int ret = -ENOSPC;
 940         void *paddr;
 941         struct bitmap_storage *store = &bitmap->storage;
 942
 943         chunks = bitmap->counts.chunks;
 944         file = store->file;
 945
 946         if (!file && !bitmap->mddev->bitmap_info.offset) {
 947                 /* No permanent bitmap - fill with '1s'. */
 948                 store->filemap = NULL;
 949                 store->file_pages = 0;
 950                 for (i = 0; i < chunks ; i++) {
 951                         /* if the disk bit is set, set the memory bit */
 952                         int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
 953                                       >= start);
 954                         bitmap_set_memory_bits(bitmap,
 955                                                (sector_t)i << bitmap->counts.chunkshift,
 956                                                needed);
 957                 }
 958                 return 0;
 959         }
 960
 961         outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
 962         if (outofdate)
 963                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
 964                         "recovery\n", bmname(bitmap));
 965
 966         if (file && i_size_read(file->f_mapping->host) < store->bytes) {
 967                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
 968                        bmname(bitmap),
 969                        (unsigned long) i_size_read(file->f_mapping->host),
 970                        store->bytes);
 971                 goto err;
 972         }
 973
 974         oldindex = ~0L;
 975         offset = 0;
 976         if (!bitmap->mddev->bitmap_info.external)
 977                 offset = sizeof(bitmap_super_t);
 978
 979         for (i = 0; i < chunks; i++) {
 980                 int b;
 981                 index = file_page_index(&bitmap->storage, i);
 982                 bit = file_page_offset(&bitmap->storage, i);
 983                 if (index != oldindex) { /* this is a new page, read it in */
 984                         int count;
 985                         /* unmap the old page, we're done with it */
 986                         if (index == store->file_pages-1)
 987                                 count = store->bytes - index * PAGE_SIZE;
 988                         else
 989                                 count = PAGE_SIZE;
 990                         page = store->filemap[index];
 991                         if (file)
 992                                 ret = read_page(file, index, bitmap,
 993                                                 count, page);
 994                         else
 995                                 ret = read_sb_page(
 996                                         bitmap->mddev,
 997                                         bitmap->mddev->bitmap_info.offset,
 998                                         page,
 999                                         index, count);
1000
1001                         if (ret)
1002                                 goto err;
1003
1004                         oldindex = index;
1005
1006                         if (outofdate) {
1007                                 /*
1008                                  * if bitmap is out of date, dirty the
1009                                  * whole page and write it out
1010                                  */
1011                                 paddr = kmap_atomic(page);
1012                                 memset(paddr + offset, 0xff,
1013                                        PAGE_SIZE - offset);
1014                                 kunmap_atomic(paddr);
1015                                 write_page(bitmap, page, 1);
1016
1017                                 ret = -EIO;
1018                                 if (test_bit(BITMAP_WRITE_ERROR,
1019                                              &bitmap->flags))
1020                                         goto err;
1021                         }
1022                 }
1023                 paddr = kmap_atomic(page);
1024                 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
1025                         b = test_bit(bit, paddr);
1026                 else
1027                         b = test_bit_le(bit, paddr);
1028                 kunmap_atomic(paddr);
1029                 if (b) {
1030                         /* if the disk bit is set, set the memory bit */
1031                         int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
1032                                       >= start);
1033                         bitmap_set_memory_bits(bitmap,
1034                                                (sector_t)i << bitmap->counts.chunkshift,
1035                                                needed);
1036                         bit_cnt++;
1037                 }
1038                 offset = 0;
1039         }
1040
1041         printk(KERN_INFO "%s: bitmap initialized from disk: "
1042                "read %lu pages, set %lu of %lu bits\n",
1043                bmname(bitmap), store->file_pages,
1044                bit_cnt, chunks);
1045
1046         return 0;
1047
1048  err:
1049         printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
1050                bmname(bitmap), ret);
1051         return ret;
1052 }
1053
1054 void bitmap_write_all(struct bitmap *bitmap)
1055 {
1056         /* We don't actually write all bitmap blocks here,
1057          * just flag them as needing to be written
1058          */
1059         int i;
1060
1061         if (!bitmap || !bitmap->storage.filemap)
1062                 return;
1063         if (bitmap->storage.file)
1064                 /* Only one copy, so nothing needed */
1065                 return;
1066
1067         for (i = 0; i < bitmap->storage.file_pages; i++)
1068                 set_page_attr(bitmap, i,
1069                               BITMAP_PAGE_NEEDWRITE);
1070         bitmap->allclean = 0;
1071 }
1072
1073 static void bitmap_count_page(struct bitmap_counts *bitmap,
1074                               sector_t offset, int inc)
1075 {
1076         sector_t chunk = offset >> bitmap->chunkshift;
1077         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1078         bitmap->bp[page].count += inc;
1079         bitmap_checkfree(bitmap, page);
1080 }
1081
1082 static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
1083 {
1084         sector_t chunk = offset >> bitmap->chunkshift;
1085         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1086         struct bitmap_page *bp = &bitmap->bp[page];
1087
1088         if (!bp->pending)
1089                 bp->pending = 1;
1090 }
1091
1092 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1093                                             sector_t offset, sector_t *blocks,
1094                                             int create);
1095
1096 /*
1097  * bitmap daemon -- periodically wakes up to clean bits and flush pages
1098  *                      out to disk
1099  */
1100
1101 void bitmap_daemon_work(struct mddev *mddev)
1102 {
1103         struct bitmap *bitmap;
1104         unsigned long j;
1105         unsigned long nextpage;
1106         sector_t blocks;
1107         struct bitmap_counts *counts;
1108
1109         /* Use a mutex to guard daemon_work against
1110          * bitmap_destroy.
1111          */
1112         mutex_lock(&mddev->bitmap_info.mutex);
1113         bitmap = mddev->bitmap;
1114         if (bitmap == NULL) {
1115                 mutex_unlock(&mddev->bitmap_info.mutex);
1116                 return;
1117         }
1118         if (time_before(jiffies, bitmap->daemon_lastrun
1119                         + mddev->bitmap_info.daemon_sleep))
1120                 goto done;
1121
1122         bitmap->daemon_lastrun = jiffies;
1123         if (bitmap->allclean) {
1124                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1125                 goto done;
1126         }
1127         bitmap->allclean = 1;
1128
1129         /* Any file-page which is PENDING now needs to be written.
1130          * So set NEEDWRITE now, then after we make any last-minute changes
1131          * we will write it.
1132          */
1133         for (j = 0; j < bitmap->storage.file_pages; j++)
1134                 if (test_and_clear_page_attr(bitmap, j,
1135                                              BITMAP_PAGE_PENDING))
1136                         set_page_attr(bitmap, j,
1137                                       BITMAP_PAGE_NEEDWRITE);
1138
1139         if (bitmap->need_sync &&
1140             mddev->bitmap_info.external == 0) {
1141                 /* Arrange for superblock update as well as
1142                  * other changes */
1143                 bitmap_super_t *sb;
1144                 bitmap->need_sync = 0;
1145                 if (bitmap->storage.filemap) {
1146                         sb = kmap_atomic(bitmap->storage.sb_page);
1147                         sb->events_cleared =
1148                                 cpu_to_le64(bitmap->events_cleared);
1149                         kunmap_atomic(sb);
1150                         set_page_attr(bitmap, 0,
1151                                       BITMAP_PAGE_NEEDWRITE);
1152                 }
1153         }
1154         /* Now look at the bitmap counters and if any are '2' or '1',
1155          * decrement and handle accordingly.
1156          */
1157         counts = &bitmap->counts;
1158         spin_lock_irq(&counts->lock);
1159         nextpage = 0;
1160         for (j = 0; j < counts->chunks; j++) {
1161                 bitmap_counter_t *bmc;
1162                 sector_t  block = (sector_t)j << counts->chunkshift;
1163
1164                 if (j == nextpage) {
1165                         nextpage += PAGE_COUNTER_RATIO;
1166                         if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
1167                                 j |= PAGE_COUNTER_MASK;
1168                                 continue;
1169                         }
1170                         counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
1171                 }
1172                 bmc = bitmap_get_counter(counts,
1173                                          block,
1174                                          &blocks, 0);
1175
1176                 if (!bmc) {
1177                         j |= PAGE_COUNTER_MASK;
1178                         continue;
1179                 }
1180                 if (*bmc == 1 && !bitmap->need_sync) {
1181                         /* We can clear the bit */
1182                         *bmc = 0;
1183                         bitmap_count_page(counts, block, -1);
1184                         bitmap_file_clear_bit(bitmap, block);
1185                 } else if (*bmc && *bmc <= 2) {
1186                         *bmc = 1;
1187                         bitmap_set_pending(counts, block);
1188                         bitmap->allclean = 0;
1189                 }
1190         }
1191         spin_unlock_irq(&counts->lock);
1192
1193         /* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
1194          * DIRTY pages need to be written by bitmap_unplug so it can wait
1195          * for them.
1196          * If we find any DIRTY page we stop there and let bitmap_unplug
1197          * handle all the rest.  This is important in the case where
1198          * the first blocking holds the superblock and it has been updated.
1199          * We mustn't write any other blocks before the superblock.
1200          */
1201         for (j = 0;
1202              j < bitmap->storage.file_pages
1203                      && !test_bit(BITMAP_STALE, &bitmap->flags);
1204              j++) {
1205
1206                 if (test_page_attr(bitmap, j,
1207                                    BITMAP_PAGE_DIRTY))
1208                         /* bitmap_unplug will handle the rest */
1209                         break;
1210                 if (test_and_clear_page_attr(bitmap, j,
1211                                              BITMAP_PAGE_NEEDWRITE)) {
1212                         write_page(bitmap, bitmap->storage.filemap[j], 0);
1213                 }
1214         }
1215
1216  done:
1217         if (bitmap->allclean == 0)
1218                 mddev->thread->timeout =
1219                         mddev->bitmap_info.daemon_sleep;
1220         mutex_unlock(&mddev->bitmap_info.mutex);
1221 }
1222
1223 static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap,
1224                                             sector_t offset, sector_t *blocks,
1225                                             int create)
1226 __releases(bitmap->lock)
1227 __acquires(bitmap->lock)
1228 {
1229         /* If 'create', we might release the lock and reclaim it.
1230          * The lock must have been taken with interrupts enabled.
1231          * If !create, we don't release the lock.
1232          */
1233         sector_t chunk = offset >> bitmap->chunkshift;
1234         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1235         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1236         sector_t csize;
1237         int err;
1238
1239         err = bitmap_checkpage(bitmap, page, create);
1240
1241         if (bitmap->bp[page].hijacked ||
1242             bitmap->bp[page].map == NULL)
1243                 csize = ((sector_t)1) << (bitmap->chunkshift +
1244                                           PAGE_COUNTER_SHIFT - 1);
1245         else
1246                 csize = ((sector_t)1) << bitmap->chunkshift;
1247         *blocks = csize - (offset & (csize - 1));
1248
1249         if (err < 0)
1250                 return NULL;
1251
1252         /* now locked ... */
1253
1254         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1255                 /* should we use the first or second counter field
1256                  * of the hijacked pointer? */
1257                 int hi = (pageoff > PAGE_COUNTER_MASK);
1258                 return  &((bitmap_counter_t *)
1259                           &bitmap->bp[page].map)[hi];
1260         } else /* page is allocated */
1261                 return (bitmap_counter_t *)
1262                         &(bitmap->bp[page].map[pageoff]);
1263 }
1264
1265 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1266 {
1267         if (!bitmap)
1268                 return 0;
1269
1270         if (behind) {
1271                 int bw;
1272                 atomic_inc(&bitmap->behind_writes);
1273                 bw = atomic_read(&bitmap->behind_writes);
1274                 if (bw > bitmap->behind_writes_used)
1275                         bitmap->behind_writes_used = bw;
1276
1277                 pr_debug("inc write-behind count %d/%lu\n",
1278                          bw, bitmap->mddev->bitmap_info.max_write_behind);
1279         }
1280
1281         while (sectors) {
1282                 sector_t blocks;
1283                 bitmap_counter_t *bmc;
1284
1285                 spin_lock_irq(&bitmap->counts.lock);
1286                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
1287                 if (!bmc) {
1288                         spin_unlock_irq(&bitmap->counts.lock);
1289                         return 0;
1290                 }
1291
1292                 if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
1293                         DEFINE_WAIT(__wait);
1294                         /* note that it is safe to do the prepare_to_wait
1295                          * after the test as long as we do it before dropping
1296                          * the spinlock.
1297                          */
1298                         prepare_to_wait(&bitmap->overflow_wait, &__wait,
1299                                         TASK_UNINTERRUPTIBLE);
1300                         spin_unlock_irq(&bitmap->counts.lock);
1301                         schedule();
1302                         finish_wait(&bitmap->overflow_wait, &__wait);
1303                         continue;
1304                 }
1305
1306                 switch (*bmc) {
1307                 case 0:
1308                         bitmap_file_set_bit(bitmap, offset);
1309                         bitmap_count_page(&bitmap->counts, offset, 1);
1310                         /* fall through */
1311                 case 1:
1312                         *bmc = 2;
1313                 }
1314
1315                 (*bmc)++;
1316
1317                 spin_unlock_irq(&bitmap->counts.lock);
1318
1319                 offset += blocks;
1320                 if (sectors > blocks)
1321                         sectors -= blocks;
1322                 else
1323                         sectors = 0;
1324         }
1325         return 0;
1326 }
1327 EXPORT_SYMBOL(bitmap_startwrite);
1328
1329 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1330                      int success, int behind)
1331 {
1332         if (!bitmap)
1333                 return;
1334         if (behind) {
1335                 if (atomic_dec_and_test(&bitmap->behind_writes))
1336                         wake_up(&bitmap->behind_wait);
1337                 pr_debug("dec write-behind count %d/%lu\n",
1338                          atomic_read(&bitmap->behind_writes),
1339                          bitmap->mddev->bitmap_info.max_write_behind);
1340         }
1341
1342         while (sectors) {
1343                 sector_t blocks;
1344                 unsigned long flags;
1345                 bitmap_counter_t *bmc;
1346
1347                 spin_lock_irqsave(&bitmap->counts.lock, flags);
1348                 bmc = bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
1349                 if (!bmc) {
1350                         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1351                         return;
1352                 }
1353
1354                 if (success && !bitmap->mddev->degraded &&
1355                     bitmap->events_cleared < bitmap->mddev->events) {
1356                         bitmap->events_cleared = bitmap->mddev->events;
1357                         bitmap->need_sync = 1;
1358                         sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
1359                 }
1360
1361                 if (!success && !NEEDED(*bmc))
1362                         *bmc |= NEEDED_MASK;
1363
1364                 if (COUNTER(*bmc) == COUNTER_MAX)
1365                         wake_up(&bitmap->overflow_wait);
1366
1367                 (*bmc)--;
1368                 if (*bmc <= 2) {
1369                         bitmap_set_pending(&bitmap->counts, offset);
1370                         bitmap->allclean = 0;
1371                 }
1372                 spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1373                 offset += blocks;
1374                 if (sectors > blocks)
1375                         sectors -= blocks;
1376                 else
1377                         sectors = 0;
1378         }
1379 }
1380 EXPORT_SYMBOL(bitmap_endwrite);
1381
1382 static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1383                                int degraded)
1384 {
1385         bitmap_counter_t *bmc;
1386         int rv;
1387         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1388                 *blocks = 1024;
1389                 return 1; /* always resync if no bitmap */
1390         }
1391         spin_lock_irq(&bitmap->counts.lock);
1392         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1393         rv = 0;
1394         if (bmc) {
1395                 /* locked */
1396                 if (RESYNC(*bmc))
1397                         rv = 1;
1398                 else if (NEEDED(*bmc)) {
1399                         rv = 1;
1400                         if (!degraded) { /* don't set/clear bits if degraded */
1401                                 *bmc |= RESYNC_MASK;
1402                                 *bmc &= ~NEEDED_MASK;
1403                         }
1404                 }
1405         }
1406         spin_unlock_irq(&bitmap->counts.lock);
1407         return rv;
1408 }
1409
1410 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
1411                       int degraded)
1412 {
1413         /* bitmap_start_sync must always report on multiples of whole
1414          * pages, otherwise resync (which is very PAGE_SIZE based) will
1415          * get confused.
1416          * So call __bitmap_start_sync repeatedly (if needed) until
1417          * At least PAGE_SIZE>>9 blocks are covered.
1418          * Return the 'or' of the result.
1419          */
1420         int rv = 0;
1421         sector_t blocks1;
1422
1423         *blocks = 0;
1424         while (*blocks < (PAGE_SIZE>>9)) {
1425                 rv |= __bitmap_start_sync(bitmap, offset,
1426                                           &blocks1, degraded);
1427                 offset += blocks1;
1428                 *blocks += blocks1;
1429         }
1430         return rv;
1431 }
1432 EXPORT_SYMBOL(bitmap_start_sync);
1433
1434 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
1435 {
1436         bitmap_counter_t *bmc;
1437         unsigned long flags;
1438
1439         if (bitmap == NULL) {
1440                 *blocks = 1024;
1441                 return;
1442         }
1443         spin_lock_irqsave(&bitmap->counts.lock, flags);
1444         bmc = bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
1445         if (bmc == NULL)
1446                 goto unlock;
1447         /* locked */
1448         if (RESYNC(*bmc)) {
1449                 *bmc &= ~RESYNC_MASK;
1450
1451                 if (!NEEDED(*bmc) && aborted)
1452                         *bmc |= NEEDED_MASK;
1453                 else {
1454                         if (*bmc <= 2) {
1455                                 bitmap_set_pending(&bitmap->counts, offset);
1456                                 bitmap->allclean = 0;
1457                         }
1458                 }
1459         }
1460  unlock:
1461         spin_unlock_irqrestore(&bitmap->counts.lock, flags);
1462 }
1463 EXPORT_SYMBOL(bitmap_end_sync);
1464
1465 void bitmap_close_sync(struct bitmap *bitmap)
1466 {
1467         /* Sync has finished, and any bitmap chunks that weren't synced
1468          * properly have been aborted.  It remains to us to clear the
1469          * RESYNC bit wherever it is still on
1470          */
1471         sector_t sector = 0;
1472         sector_t blocks;
1473         if (!bitmap)
1474                 return;
1475         while (sector < bitmap->mddev->resync_max_sectors) {
1476                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1477                 sector += blocks;
1478         }
1479 }
1480 EXPORT_SYMBOL(bitmap_close_sync);
1481
1482 void bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector)
1483 {
1484         sector_t s = 0;
1485         sector_t blocks;
1486
1487         if (!bitmap)
1488                 return;
1489         if (sector == 0) {
1490                 bitmap->last_end_sync = jiffies;
1491                 return;
1492         }
1493         if (time_before(jiffies, (bitmap->last_end_sync
1494                                   + bitmap->mddev->bitmap_info.daemon_sleep)))
1495                 return;
1496         wait_event(bitmap->mddev->recovery_wait,
1497                    atomic_read(&bitmap->mddev->recovery_active) == 0);
1498
1499         bitmap->mddev->curr_resync_completed = sector;
1500         set_bit(MD_CHANGE_CLEAN, &bitmap->mddev->flags);
1501         sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
1502         s = 0;
1503         while (s < sector && s < bitmap->mddev->resync_max_sectors) {
1504                 bitmap_end_sync(bitmap, s, &blocks, 0);
1505                 s += blocks;
1506         }
1507         bitmap->last_end_sync = jiffies;
1508         sysfs_notify(&bitmap->mddev->kobj, NULL, "sync_completed");
1509 }
1510 EXPORT_SYMBOL(bitmap_cond_end_sync);
1511
1512 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1513 {
1514         /* For each chunk covered by any of these sectors, set the
1515          * counter to 2 and possibly set resync_needed.  They should all
1516          * be 0 at this point
1517          */
1518
1519         sector_t secs;
1520         bitmap_counter_t *bmc;
1521         spin_lock_irq(&bitmap->counts.lock);
1522         bmc = bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
1523         if (!bmc) {
1524                 spin_unlock_irq(&bitmap->counts.lock);
1525                 return;
1526         }
1527         if (!*bmc) {
1528                 *bmc = 2 | (needed ? NEEDED_MASK : 0);
1529                 bitmap_count_page(&bitmap->counts, offset, 1);
1530                 bitmap_set_pending(&bitmap->counts, offset);
1531                 bitmap->allclean = 0;
1532         }
1533         spin_unlock_irq(&bitmap->counts.lock);
1534 }
1535
1536 /* dirty the memory and file bits for bitmap chunks "s" to "e" */
1537 void bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
1538 {
1539         unsigned long chunk;
1540
1541         for (chunk = s; chunk <= e; chunk++) {
1542                 sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
1543                 bitmap_set_memory_bits(bitmap, sec, 1);
1544                 bitmap_file_set_bit(bitmap, sec);
1545                 if (sec < bitmap->mddev->recovery_cp)
1546                         /* We are asserting that the array is dirty,
1547                          * so move the recovery_cp address back so
1548                          * that it is obvious that it is dirty
1549                          */
1550                         bitmap->mddev->recovery_cp = sec;
1551         }
1552 }
1553
1554 /*
1555  * flush out any pending updates
1556  */
1557 void bitmap_flush(struct mddev *mddev)
1558 {
1559         struct bitmap *bitmap = mddev->bitmap;
1560         long sleep;
1561
1562         if (!bitmap) /* there was no bitmap */
1563                 return;
1564
1565         /* run the daemon_work three time to ensure everything is flushed
1566          * that can be
1567          */
1568         sleep = mddev->bitmap_info.daemon_sleep * 2;
1569         bitmap->daemon_lastrun -= sleep;
1570         bitmap_daemon_work(mddev);
1571         bitmap->daemon_lastrun -= sleep;
1572         bitmap_daemon_work(mddev);
1573         bitmap->daemon_lastrun -= sleep;
1574         bitmap_daemon_work(mddev);
1575         bitmap_update_sb(bitmap);
1576 }
1577
1578 /*
1579  * free memory that was allocated
1580  */
1581 static void bitmap_free(struct bitmap *bitmap)
1582 {
1583         unsigned long k, pages;
1584         struct bitmap_page *bp;
1585
1586         if (!bitmap) /* there was no bitmap */
1587                 return;
1588
1589         /* Shouldn't be needed - but just in case.... */
1590         wait_event(bitmap->write_wait,
1591                    atomic_read(&bitmap->pending_writes) == 0);
1592
1593         /* release the bitmap file  */
1594         bitmap_file_unmap(&bitmap->storage);
1595
1596         bp = bitmap->counts.bp;
1597         pages = bitmap->counts.pages;
1598
1599         /* free all allocated memory */
1600
1601         if (bp) /* deallocate the page memory */
1602                 for (k = 0; k < pages; k++)
1603                         if (bp[k].map && !bp[k].hijacked)
1604                                 kfree(bp[k].map);
1605         kfree(bp);
1606         kfree(bitmap);
1607 }
1608
1609 void bitmap_destroy(struct mddev *mddev)
1610 {
1611         struct bitmap *bitmap = mddev->bitmap;
1612
1613         if (!bitmap) /* there was no bitmap */
1614                 return;
1615
1616         mutex_lock(&mddev->bitmap_info.mutex);
1617         mddev->bitmap = NULL; /* disconnect from the md device */
1618         mutex_unlock(&mddev->bitmap_info.mutex);
1619         if (mddev->thread)
1620                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1621
1622         if (bitmap->sysfs_can_clear)
1623                 sysfs_put(bitmap->sysfs_can_clear);
1624
1625         bitmap_free(bitmap);
1626 }
1627
1628 /*
1629  * initialize the bitmap structure
1630  * if this returns an error, bitmap_destroy must be called to do clean up
1631  */
1632 int bitmap_create(struct mddev *mddev)
1633 {
1634         struct bitmap *bitmap;
1635         sector_t blocks = mddev->resync_max_sectors;
1636         struct file *file = mddev->bitmap_info.file;
1637         int err;
1638         struct sysfs_dirent *bm = NULL;
1639
1640         BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
1641
1642         BUG_ON(file && mddev->bitmap_info.offset);
1643
1644         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1645         if (!bitmap)
1646                 return -ENOMEM;
1647
1648         spin_lock_init(&bitmap->counts.lock);
1649         atomic_set(&bitmap->pending_writes, 0);
1650         init_waitqueue_head(&bitmap->write_wait);
1651         init_waitqueue_head(&bitmap->overflow_wait);
1652         init_waitqueue_head(&bitmap->behind_wait);
1653
1654         bitmap->mddev = mddev;
1655
1656         if (mddev->kobj.sd)
1657                 bm = sysfs_get_dirent(mddev->kobj.sd, NULL, "bitmap");
1658         if (bm) {
1659                 bitmap->sysfs_can_clear = sysfs_get_dirent(bm, NULL, "can_clear");
1660                 sysfs_put(bm);
1661         } else
1662                 bitmap->sysfs_can_clear = NULL;
1663
1664         bitmap->storage.file = file;
1665         if (file) {
1666                 get_file(file);
1667                 /* As future accesses to this file will use bmap,
1668                  * and bypass the page cache, we must sync the file
1669                  * first.
1670                  */
1671                 vfs_fsync(file, 1);
1672         }
1673         /* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
1674         if (!mddev->bitmap_info.external) {
1675                 /*
1676                  * If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
1677                  * instructing us to create a new on-disk bitmap instance.
1678                  */
1679                 if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
1680                         err = bitmap_new_disk_sb(bitmap);
1681                 else
1682                         err = bitmap_read_sb(bitmap);
1683         } else {
1684                 err = 0;
1685                 if (mddev->bitmap_info.chunksize == 0 ||
1686                     mddev->bitmap_info.daemon_sleep == 0)
1687                         /* chunksize and time_base need to be
1688                          * set first. */
1689                         err = -EINVAL;
1690         }
1691         if (err)
1692                 goto error;
1693
1694         bitmap->daemon_lastrun = jiffies;
1695         err = bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
1696         if (err)
1697                 goto error;
1698
1699         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1700                bitmap->counts.pages, bmname(bitmap));
1701
1702         mddev->bitmap = bitmap;
1703         return test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
1704
1705  error:
1706         bitmap_free(bitmap);
1707         return err;
1708 }
1709
1710 int bitmap_load(struct mddev *mddev)
1711 {
1712         int err = 0;
1713         sector_t start = 0;
1714         sector_t sector = 0;
1715         struct bitmap *bitmap = mddev->bitmap;
1716
1717         if (!bitmap)
1718                 goto out;
1719
1720         /* Clear out old bitmap info first:  Either there is none, or we
1721          * are resuming after someone else has possibly changed things,
1722          * so we should forget old cached info.
1723          * All chunks should be clean, but some might need_sync.
1724          */
1725         while (sector < mddev->resync_max_sectors) {
1726                 sector_t blocks;
1727                 bitmap_start_sync(bitmap, sector, &blocks, 0);
1728                 sector += blocks;
1729         }
1730         bitmap_close_sync(bitmap);
1731
1732         if (mddev->degraded == 0
1733             || bitmap->events_cleared == mddev->events)
1734                 /* no need to keep dirty bits to optimise a
1735                  * re-add of a missing device */
1736                 start = mddev->recovery_cp;
1737
1738         mutex_lock(&mddev->bitmap_info.mutex);
1739         err = bitmap_init_from_disk(bitmap, start);
1740         mutex_unlock(&mddev->bitmap_info.mutex);
1741
1742         if (err)
1743                 goto out;
1744         clear_bit(BITMAP_STALE, &bitmap->flags);
1745
1746         /* Kick recovery in case any bits were set */
1747         set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
1748
1749         mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
1750         md_wakeup_thread(mddev->thread);
1751
1752         bitmap_update_sb(bitmap);
1753
1754         if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
1755                 err = -EIO;
1756 out:
1757         return err;
1758 }
1759 EXPORT_SYMBOL_GPL(bitmap_load);
1760
1761 void bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
1762 {
1763         unsigned long chunk_kb;
1764         struct bitmap_counts *counts;
1765
1766         if (!bitmap)
1767                 return;
1768
1769         counts = &bitmap->counts;
1770
1771         chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
1772         seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
1773                    "%lu%s chunk",
1774                    counts->pages - counts->missing_pages,
1775                    counts->pages,
1776                    (counts->pages - counts->missing_pages)
1777                    << (PAGE_SHIFT - 10),
1778                    chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
1779                    chunk_kb ? "KB" : "B");
1780         if (bitmap->storage.file) {
1781                 seq_printf(seq, ", file: ");
1782                 seq_path(seq, &bitmap->storage.file->f_path, " \t\n");
1783         }
1784
1785         seq_printf(seq, "\n");
1786 }
1787
1788 int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
1789                   int chunksize, int init)
1790 {
1791         /* If chunk_size is 0, choose an appropriate chunk size.
1792          * Then possibly allocate new storage space.
1793          * Then quiesce, copy bits, replace bitmap, and re-start
1794          *
1795          * This function is called both to set up the initial bitmap
1796          * and to resize the bitmap while the array is active.
1797          * If this happens as a result of the array being resized,
1798          * chunksize will be zero, and we need to choose a suitable
1799          * chunksize, otherwise we use what we are given.
1800          */
1801         struct bitmap_storage store;
1802         struct bitmap_counts old_counts;
1803         unsigned long chunks;
1804         sector_t block;
1805         sector_t old_blocks, new_blocks;
1806         int chunkshift;
1807         int ret = 0;
1808         long pages;
1809         struct bitmap_page *new_bp;
1810
1811         if (chunksize == 0) {
1812                 /* If there is enough space, leave the chunk size unchanged,
1813                  * else increase by factor of two until there is enough space.
1814                  */
1815                 long bytes;
1816                 long space = bitmap->mddev->bitmap_info.space;
1817
1818                 if (space == 0) {
1819                         /* We don't know how much space there is, so limit
1820                          * to current size - in sectors.
1821                          */
1822                         bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
1823                         if (!bitmap->mddev->bitmap_info.external)
1824                                 bytes += sizeof(bitmap_super_t);
1825                         space = DIV_ROUND_UP(bytes, 512);
1826                         bitmap->mddev->bitmap_info.space = space;
1827                 }
1828                 chunkshift = bitmap->counts.chunkshift;
1829                 chunkshift--;
1830                 do {
1831                         /* 'chunkshift' is shift from block size to chunk size */
1832                         chunkshift++;
1833                         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1834                         bytes = DIV_ROUND_UP(chunks, 8);
1835                         if (!bitmap->mddev->bitmap_info.external)
1836                                 bytes += sizeof(bitmap_super_t);
1837                 } while (bytes > (space << 9));
1838         } else
1839                 chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
1840
1841         chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
1842         memset(&store, 0, sizeof(store));
1843         if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
1844                 ret = bitmap_storage_alloc(&store, chunks,
1845                                            !bitmap->mddev->bitmap_info.external);
1846         if (ret)
1847                 goto err;
1848
1849         pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
1850
1851         new_bp = kzalloc(pages * sizeof(*new_bp), GFP_KERNEL);
1852         ret = -ENOMEM;
1853         if (!new_bp) {
1854                 bitmap_file_unmap(&store);
1855                 goto err;
1856         }
1857
1858         if (!init)
1859                 bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
1860
1861         store.file = bitmap->storage.file;
1862         bitmap->storage.file = NULL;
1863
1864         if (store.sb_page && bitmap->storage.sb_page)
1865                 memcpy(page_address(store.sb_page),
1866                        page_address(bitmap->storage.sb_page),
1867                        sizeof(bitmap_super_t));
1868         bitmap_file_unmap(&bitmap->storage);
1869         bitmap->storage = store;
1870
1871         old_counts = bitmap->counts;
1872         bitmap->counts.bp = new_bp;
1873         bitmap->counts.pages = pages;
1874         bitmap->counts.missing_pages = pages;
1875         bitmap->counts.chunkshift = chunkshift;
1876         bitmap->counts.chunks = chunks;
1877         bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
1878                                                      BITMAP_BLOCK_SHIFT);
1879
1880         blocks = min(old_counts.chunks << old_counts.chunkshift,
1881                      chunks << chunkshift);
1882
1883         spin_lock_irq(&bitmap->counts.lock);
1884         for (block = 0; block < blocks; ) {
1885                 bitmap_counter_t *bmc_old, *bmc_new;
1886                 int set;
1887
1888                 bmc_old = bitmap_get_counter(&old_counts, block,
1889                                              &old_blocks, 0);
1890                 set = bmc_old && NEEDED(*bmc_old);
1891
1892                 if (set) {
1893                         bmc_new = bitmap_get_counter(&bitmap->counts, block,
1894                                                      &new_blocks, 1);
1895                         if (*bmc_new == 0) {
1896                                 /* need to set on-disk bits too. */
1897                                 sector_t end = block + new_blocks;
1898                                 sector_t start = block >> chunkshift;
1899                                 start <<= chunkshift;
1900                                 while (start < end) {
1901                                         bitmap_file_set_bit(bitmap, block);
1902                                         start += 1 << chunkshift;
1903                                 }
1904                                 *bmc_new = 2;
1905                                 bitmap_count_page(&bitmap->counts,
1906                                                   block, 1);
1907                                 bitmap_set_pending(&bitmap->counts,
1908                                                    block);
1909                         }
1910                         *bmc_new |= NEEDED_MASK;
1911                         if (new_blocks < old_blocks)
1912                                 old_blocks = new_blocks;
1913                 }
1914                 block += old_blocks;
1915         }
1916
1917         if (!init) {
1918                 int i;
1919                 while (block < (chunks << chunkshift)) {
1920                         bitmap_counter_t *bmc;
1921                         bmc = bitmap_get_counter(&bitmap->counts, block,
1922                                                  &new_blocks, 1);
1923                         if (bmc) {
1924                                 /* new space.  It needs to be resynced, so
1925                                  * we set NEEDED_MASK.
1926                                  */
1927                                 if (*bmc == 0) {
1928                                         *bmc = NEEDED_MASK | 2;
1929                                         bitmap_count_page(&bitmap->counts,
1930                                                           block, 1);
1931                                         bitmap_set_pending(&bitmap->counts,
1932                                                            block);
1933                                 }
1934                         }
1935                         block += new_blocks;
1936                 }
1937                 for (i = 0; i < bitmap->storage.file_pages; i++)
1938                         set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
1939         }
1940         spin_unlock_irq(&bitmap->counts.lock);
1941
1942         if (!init) {
1943                 bitmap_unplug(bitmap);
1944                 bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
1945         }
1946         ret = 0;
1947 err:
1948         return ret;
1949 }
1950 EXPORT_SYMBOL_GPL(bitmap_resize);
1951
1952 static ssize_t
1953 location_show(struct mddev *mddev, char *page)
1954 {
1955         ssize_t len;
1956         if (mddev->bitmap_info.file)
1957                 len = sprintf(page, "file");
1958         else if (mddev->bitmap_info.offset)
1959                 len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
1960         else
1961                 len = sprintf(page, "none");
1962         len += sprintf(page+len, "\n");
1963         return len;
1964 }
1965
1966 static ssize_t
1967 location_store(struct mddev *mddev, const char *buf, size_t len)
1968 {
1969
1970         if (mddev->pers) {
1971                 if (!mddev->pers->quiesce)
1972                         return -EBUSY;
1973                 if (mddev->recovery || mddev->sync_thread)
1974                         return -EBUSY;
1975         }
1976
1977         if (mddev->bitmap || mddev->bitmap_info.file ||
1978             mddev->bitmap_info.offset) {
1979                 /* bitmap already configured.  Only option is to clear it */
1980                 if (strncmp(buf, "none", 4) != 0)
1981                         return -EBUSY;
1982                 if (mddev->pers) {
1983                         mddev->pers->quiesce(mddev, 1);
1984                         bitmap_destroy(mddev);
1985                         mddev->pers->quiesce(mddev, 0);
1986                 }
1987                 mddev->bitmap_info.offset = 0;
1988                 if (mddev->bitmap_info.file) {
1989                         struct file *f = mddev->bitmap_info.file;
1990                         mddev->bitmap_info.file = NULL;
1991                         restore_bitmap_write_access(f);
1992                         fput(f);
1993                 }
1994         } else {
1995                 /* No bitmap, OK to set a location */
1996                 long long offset;
1997                 if (strncmp(buf, "none", 4) == 0)
1998                         /* nothing to be done */;
1999                 else if (strncmp(buf, "file:", 5) == 0) {
2000                         /* Not supported yet */
2001                         return -EINVAL;
2002                 } else {
2003                         int rv;
2004                         if (buf[0] == '+')
2005                                 rv = kstrtoll(buf+1, 10, &offset);
2006                         else
2007                                 rv = kstrtoll(buf, 10, &offset);
2008                         if (rv)
2009                                 return rv;
2010                         if (offset == 0)
2011                                 return -EINVAL;
2012                         if (mddev->bitmap_info.external == 0 &&
2013                             mddev->major_version == 0 &&
2014                             offset != mddev->bitmap_info.default_offset)
2015                                 return -EINVAL;
2016                         mddev->bitmap_info.offset = offset;
2017                         if (mddev->pers) {
2018                                 mddev->pers->quiesce(mddev, 1);
2019                                 rv = bitmap_create(mddev);
2020                                 if (!rv)
2021                                         rv = bitmap_load(mddev);
2022                                 if (rv) {
2023                                         bitmap_destroy(mddev);
2024                                         mddev->bitmap_info.offset = 0;
2025                                 }
2026                                 mddev->pers->quiesce(mddev, 0);
2027                                 if (rv)
2028                                         return rv;
2029                         }
2030                 }
2031         }
2032         if (!mddev->external) {
2033                 /* Ensure new bitmap info is stored in
2034                  * metadata promptly.
2035                  */
2036                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
2037                 md_wakeup_thread(mddev->thread);
2038         }
2039         return len;
2040 }
2041
2042 static struct md_sysfs_entry bitmap_location =
2043 __ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
2044
2045 /* 'bitmap/space' is the space available at 'location' for the
2046  * bitmap.  This allows the kernel to know when it is safe to
2047  * resize the bitmap to match a resized array.
2048  */
2049 static ssize_t
2050 space_show(struct mddev *mddev, char *page)
2051 {
2052         return sprintf(page, "%lu\n", mddev->bitmap_info.space);
2053 }
2054
2055 static ssize_t
2056 space_store(struct mddev *mddev, const char *buf, size_t len)
2057 {
2058         unsigned long sectors;
2059         int rv;
2060
2061         rv = kstrtoul(buf, 10, &sectors);
2062         if (rv)
2063                 return rv;
2064
2065         if (sectors == 0)
2066                 return -EINVAL;
2067
2068         if (mddev->bitmap &&
2069             sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
2070                 return -EFBIG; /* Bitmap is too big for this small space */
2071
2072         /* could make sure it isn't too big, but that isn't really
2073          * needed - user-space should be careful.
2074          */
2075         mddev->bitmap_info.space = sectors;
2076         return len;
2077 }
2078
2079 static struct md_sysfs_entry bitmap_space =
2080 __ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
2081
2082 static ssize_t
2083 timeout_show(struct mddev *mddev, char *page)
2084 {
2085         ssize_t len;
2086         unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
2087         unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
2088
2089         len = sprintf(page, "%lu", secs);
2090         if (jifs)
2091                 len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
2092         len += sprintf(page+len, "\n");
2093         return len;
2094 }
2095
2096 static ssize_t
2097 timeout_store(struct mddev *mddev, const char *buf, size_t len)
2098 {
2099         /* timeout can be set at any time */
2100         unsigned long timeout;
2101         int rv = strict_strtoul_scaled(buf, &timeout, 4);
2102         if (rv)
2103                 return rv;
2104
2105         /* just to make sure we don't overflow... */
2106         if (timeout >= LONG_MAX / HZ)
2107                 return -EINVAL;
2108
2109         timeout = timeout * HZ / 10000;
2110
2111         if (timeout >= MAX_SCHEDULE_TIMEOUT)
2112                 timeout = MAX_SCHEDULE_TIMEOUT-1;
2113         if (timeout < 1)
2114                 timeout = 1;
2115         mddev->bitmap_info.daemon_sleep = timeout;
2116         if (mddev->thread) {
2117                 /* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
2118                  * the bitmap is all clean and we don't need to
2119                  * adjust the timeout right now
2120                  */
2121                 if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
2122                         mddev->thread->timeout = timeout;
2123                         md_wakeup_thread(mddev->thread);
2124                 }
2125         }
2126         return len;
2127 }
2128
2129 static struct md_sysfs_entry bitmap_timeout =
2130 __ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
2131
2132 static ssize_t
2133 backlog_show(struct mddev *mddev, char *page)
2134 {
2135         return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
2136 }
2137
2138 static ssize_t
2139 backlog_store(struct mddev *mddev, const char *buf, size_t len)
2140 {
2141         unsigned long backlog;
2142         int rv = kstrtoul(buf, 10, &backlog);
2143         if (rv)
2144                 return rv;
2145         if (backlog > COUNTER_MAX)
2146                 return -EINVAL;
2147         mddev->bitmap_info.max_write_behind = backlog;
2148         return len;
2149 }
2150
2151 static struct md_sysfs_entry bitmap_backlog =
2152 __ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
2153
2154 static ssize_t
2155 chunksize_show(struct mddev *mddev, char *page)
2156 {
2157         return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
2158 }
2159
2160 static ssize_t
2161 chunksize_store(struct mddev *mddev, const char *buf, size_t len)
2162 {
2163         /* Can only be changed when no bitmap is active */
2164         int rv;
2165         unsigned long csize;
2166         if (mddev->bitmap)
2167                 return -EBUSY;
2168         rv = kstrtoul(buf, 10, &csize);
2169         if (rv)
2170                 return rv;
2171         if (csize < 512 ||
2172             !is_power_of_2(csize))
2173                 return -EINVAL;
2174         mddev->bitmap_info.chunksize = csize;
2175         return len;
2176 }
2177
2178 static struct md_sysfs_entry bitmap_chunksize =
2179 __ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
2180
2181 static ssize_t metadata_show(struct mddev *mddev, char *page)
2182 {
2183         return sprintf(page, "%s\n", (mddev->bitmap_info.external
2184                                       ? "external" : "internal"));
2185 }
2186
2187 static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
2188 {
2189         if (mddev->bitmap ||
2190             mddev->bitmap_info.file ||
2191             mddev->bitmap_info.offset)
2192                 return -EBUSY;
2193         if (strncmp(buf, "external", 8) == 0)
2194                 mddev->bitmap_info.external = 1;
2195         else if (strncmp(buf, "internal", 8) == 0)
2196                 mddev->bitmap_info.external = 0;
2197         else
2198                 return -EINVAL;
2199         return len;
2200 }
2201
2202 static struct md_sysfs_entry bitmap_metadata =
2203 __ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2204
2205 static ssize_t can_clear_show(struct mddev *mddev, char *page)
2206 {
2207         int len;
2208         if (mddev->bitmap)
2209                 len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
2210                                              "false" : "true"));
2211         else
2212                 len = sprintf(page, "\n");
2213         return len;
2214 }
2215
2216 static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
2217 {
2218         if (mddev->bitmap == NULL)
2219                 return -ENOENT;
2220         if (strncmp(buf, "false", 5) == 0)
2221                 mddev->bitmap->need_sync = 1;
2222         else if (strncmp(buf, "true", 4) == 0) {
2223                 if (mddev->degraded)
2224                         return -EBUSY;
2225                 mddev->bitmap->need_sync = 0;
2226         } else
2227                 return -EINVAL;
2228         return len;
2229 }
2230
2231 static struct md_sysfs_entry bitmap_can_clear =
2232 __ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
2233
2234 static ssize_t
2235 behind_writes_used_show(struct mddev *mddev, char *page)
2236 {
2237         if (mddev->bitmap == NULL)
2238                 return sprintf(page, "0\n");
2239         return sprintf(page, "%lu\n",
2240                        mddev->bitmap->behind_writes_used);
2241 }
2242
2243 static ssize_t
2244 behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
2245 {
2246         if (mddev->bitmap)
2247                 mddev->bitmap->behind_writes_used = 0;
2248         return len;
2249 }
2250
2251 static struct md_sysfs_entry max_backlog_used =
2252 __ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
2253        behind_writes_used_show, behind_writes_used_reset);
2254
2255 static struct attribute *md_bitmap_attrs[] = {
2256         &bitmap_location.attr,
2257         &bitmap_space.attr,
2258         &bitmap_timeout.attr,
2259         &bitmap_backlog.attr,
2260         &bitmap_chunksize.attr,
2261         &bitmap_metadata.attr,
2262         &bitmap_can_clear.attr,
2263         &max_backlog_used.attr,
2264         NULL
2265 };
2266 struct attribute_group md_bitmap_group = {
2267         .name = "bitmap",
2268         .attrs = md_bitmap_attrs,
2269 };
2270